Priming and tamping device for explosives in blast holdes



10, 1 H. SAUVAGE 2,685,836

PRIMING AND TAMPING DEVICE FOR EXPLOSIVES IN BLAST HOLES Filed March 13 1950 INVENTOR HENRI SAUVA G E ATTORNEY-'8 Patented Aug. 10, 1954 PRIMING AND TAMPING DEVICE FOR EXPLOSIVES IN BLAST HOLES Henri Sauvage, Paris, France, assignor to LAir Liquide, Societe Anonyme pour lEtude et lExploitation des Procedes Georges Claude, Paris,

France Application March 13, 1950-, Serial No. 149,398

Claims priority, application France'Mai-ch 25, 1949 2 Claims. 1

In the operations for charging a blast hole with explosive, one generally operates in the following manner: one introduces successively in the blast hole a certain number of cartridges of explosive; before introducing the last cartridge, one opens the wrapping of the latter to place therein the igniter, then the wrapping is closed on said igniter and this last cartridge is introduced into the blast hole; then the tamping, and finally the ignition are efiected.

These successive operations require a fairly long charging time for the blast hole which it is convenient to minimise as much as possible. An appreciable saving in time in charging a blast hole is accomplished by employing the device of the present invention.

According to the present invention, one uses for the priming of the last cartridge and for the tamping of the blast hole, a priming and tamping device consisting essentially in a guide sleeve of a diameter slightly smaller than the cartridge diameter and provided with a longitudinal passage wherein the ignition means is housed; this sleeve being associated at the one of its ends which is not on the priming cartridge side, to the mechanical tamping, for instance by an auxiliary sleeve entering the first sleeve and going through the mechanical tamping from which it possibly extends.

When, by means of the tamping bar, the priming and tamping device mentioned above is introduced into the blast hole, the action of the tamping bar is exerted on the auxiliary sleeve maintaining the mechanical tamping, instead of acting directly on said mechanical tamping.

The ignition means housed in the main sleeve protrudes from said sleeve so as to enter a cavity provided in the priming cartridge. To this effect, the sleeve is provided with studs which engage into the corresponding cavities of the plate of a cap secured at the end of the priming cartridge in such a manner that the sleeve and the priming cartridge form a rigid assembly capable of being easily introduced into the blast hole.

Thus, in one operation, one can introduce, by pushing it by means of a tamping bar, the assembly constituted by the mechanical tamping, the guide sleeve enclosing the ignition means and the priming cartridge, which makes it possible to reduce in an important proportion the time of charging of the blast hole.

Figures 1 to 3 attached herewith show schematically and by way of example, one type of embodiment of the present invention, using the bell which is the object of the former patent section of the part. of the device located on the side of the opening of the blast hole. Figure 2' shows an enlarged sectional View of the assembly at the other end of the sleeve with the priming cartridge. Figure 3 is an enlarged plane View of the assembly cap of the priming cartridge to the above device.

In Figure 1 the guide sleeve shown at I is extended at one of its ends by the auxiliary sleeve 2 by means of which the mechanical tamping means 3 comprising a bell-shaped body of a substantially rigid material of the type shown and described in the co-pending application of Henri Sauvage and Emile Broville, Serial No. 121,304, filed October 14, 1949, is associated with the main sleeve I; the assembly of these two sleeves is bored with a longitudinal axial hole =4 in which the electric detonator 5 is introduced with its wires 6.

These wires may be anchored on the sleeve at the outlet of said sleeve to prevent, in case of an untimely pulling of these wires, a traction being exerted on the priming.

They may also be sealed in the axial passage of the sleeve to prevent any eventual relative motion between them and the priming and also for imposing to the ignition device a well defined position.

In Figure 2 which shows the assembly of the other end of sleeve I with the priming cartridge it, the face of the sleeve corresponding to this end is provided with studs consisting for example of three screws '8.

The detonator 8 constituting one end of the priming goes beyond the sleeve to engage into a housing 9 provided to this effect in the priming cartridge It. This priming cartridge carries at its upper part a cap ll attached to the envelope M of the priming cartridge, at the time of its manufacturing, by a wire l3 clamped against the groove E5 of the cap II. This cap is perforated with arcuate slots i2 (Figure 3) in which the screws 1 of the sleeve 1 are caused to engage, thus obtaining by this bayonet type engagement the securing of the priming cartridge with the sleeve.

The above embodiment relates to an ignition means using an electrical igniter, but it should be understood that the priming and tamping device which is the object of the present invention, is applicable also to any ignition means such as the detonating cord or the miners match.

What I claim is:

1. In a priming and mechanical tamping device for blast holes, in combination, a rigid guidesleeve the axial hole of which is adapted to guide a detonator with its igniting means, means provided at the lower end of said guide-sleeve for coupling said end with the corresponding end of a blast cartridge by maintaining the detonator in igniting engagement with said cartridge, a mechanical tamping in the shape of a bell having an aperture provided in its bottom, and an auxiliary rigid sleeve provided with a box at its lower end adapted to pass through the apertured bottom of the mechanical tamping and to engage the upper end of the guide-sleeve for securing on the latter said tamping, said auxiliary sleeve extending beyond the upper edge of the tamping.

2. In a priming and mechanical tamping device for blast holes, in combination, a rigid guidesleeve the axial hole of which is adapted to guide a detonator with its igniting means, projecting members provided on the lower end of said guidesleeve adapted to engage the corresponding end of a blast cartridge for coupling the same with the guide-sleeve by maintaining the detonator in igniting engagement with said cartridge, a

mechanical tamping in the shape of a bell having an aperture provided in its bottom, and an auxiliary rigid sleeve provided with a boss at its lower end adapted to pass through the apertured bottom of the mechanical tamping and to engage the upper end of the guide sleeve for securing on the latter said tamping, said auxiliary sleeve extending beyond the upper edge of the tamping.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 138,373 Briggs Apr. 29, 1873 1,055,922 Landaal Mar. 11, 1913 2,355,922 Minero Aug. 15, 1944 2,358,795 Djidics et al. Sept. 26, 1944 2,548,647 Blewett Apr. 10, 1951 FOREIGN PATENTS Number Country Date 3,236 Great Britain Aug. 7, 1880 of 1880 493,667 Germany July 1, 1928 

